Vulnerability · Published May 26, 2026 · Assigned by GitHub_M

CVE-2026-44723Vowpal Wabbit: Shell injection via crafted PR title in python_checks.yml allows arbitrary command execution on CI runner

Medium 5.0

In plain English

A medium-severity OS command injection in vowpal_wabbit from VowpalWabbit. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 41% of all known vulnerabilities).

Severity (CVSS 3.1)5.0Medium

Exploit odds (30 days)0.5%top 59.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

Vowpal Wabbit is a machine learning system. The workflow .github/workflows/python_checks.yml embeds ${{ github.event.pull_request.title }} directly inside double-quoted bash strings in four separate steps across four jobs, each passing it as a CLI argument to the Python test script run_tests_model_gen_and_load.py. The shell interprets the expanded string before invoking Python, allowing an attacker to break out of the quotes and execute arbitrary commands on the runner. The pull_request trigger fires on PRs targeting any branch (branches: ['*']), with no additional access gate. This vulnerability is fixed by the 998e390e80a7e8192d7849b7784bc113dbd190ad commit.

Affected products (as reported)

Vendor	Product	Versions
VowpalWabbit	vowpal_wabbit	< 998e390e80a7e8192d7849b7784bc113dbd190ad

Weakness: CWE-78, CWE-1336 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N

References

https://github.com/VowpalWabbit/vowpal_wabbit/security/advisories/GHSA-cg2g-xgg7-3xxq x_refsource_CONFIRM
https://github.com/VowpalWabbit/vowpal_wabbit/commit/998e390e80a7e8192d7849b7784bc113dbd190ad x_refsource_MISC